In both Europe and the USA attention has focussed on clean coal technology incorporating coal gasification; for example, Integrated Gasification Combined Cycle (IGCC) technologies and the capture and compression of by-product CO2 to facilitate transport (for example by pipeline) for use in enhanced oil recovery by injection into depleting fields or for injection into depleted oil or gas reservoirs for safe storage.
Increasing global concerns over the causative effect of CO2 emissions in world climate change have led to a variety of countermeasures such as increased investment in wind power, nuclear power, and planning for power plants that employ CO2 capture to reduce or eliminate by-product CO2 emissions. Many new build pulverized coal-based steam cycle power plants will suffer especially large negative impacts on costs and thermal efficiencies if, as seems likely, CO2 capture and disposal is mandated.
The increased use of natural gas for power generation is placing pressure on supplies, which in turn leads to price increases. This has also led to proposals to construct coal-based SNG plants. Without carbon capture, such plants emit large amounts of by-product CO2 to atmosphere, and are thus also likely to be subject to regulations enforcing CO2 capture and safe disposal.
There is typically a significant negative impact of CO2 capture and export upon the costs and thermal efficiencies of such energy conversion processes; for example, clean coal technology power plants and SNG plants. Typically, this impact arises from the need to compress separated gaseous CO2 from low pressure (following separation) to a pressure of around 100-150 bar (to allow transport and/or disposal underground). One aim of the current invention is to eliminate this costly gaseous compression step. Another aim is to provide a simpler process that allows CO2 capture in power generation processes. A further aim is to largely alleviate the above mentioned negative impact of CO2 capture and export upon the overall costs and thermal efficiencies.